助动词和情态动词
助动词和情态动词
助动词包括：be (is, am, are, was, were, been, being)；have (has, had, having)；do (does, did)；shall (should), will (would)
情态动词包括：can, could, (be able to)；may, might；will ,would；dare, need, must (have to)，ought to, shall, should
" be + 动词不定式"可以表示下面几种意思:
1.命令或指示。例如：
No one is to enter the room without permission.
The books are not to be taken out of the reading-room.
2.计划或安排。例如：
A new bridge is to be built over the river soon.
The expedition is to start in a week's time.
3.可能。例如：
This kind of tree is to be found in that forest.
4.应该。例如：
Such people are to be criticized.
5.表示后来发生的事，可以用来表示一种命运。例如：
They said good-bye, little knowing that they were never to meet again.
He was to regret the decision.
Note:
was (were) + 不定式完成式
这种结构表示“本来打算…，本来要…（而结果则没做）”。例如：
He was to have attended the meeting, but he fell ill.
他本来要参加会议的，但是生病了。（因此没参加）
have to 和must在表示“必须”这个意思时是很接近的，但
也有一定的区别。
1. have to 比较强调客观需要，表示因客观环境或事态促使而不得不做某事；must强调主观看法，表示主观上认为有必要做某事。例如：
I must learn another language.
（主观想法: I want to）
I have to learn another language.
（客观需要：身为一个外交官）
You must be back before 10 o'clock.
（叮嘱或命令）
You have to be back before 10 o'clock because the train is to leave at 10:05.（客观需要）
注意下面两句的含义：
Though she didn't need to, she must go.
虽然她不用去，她却偏要去。
You don't have to come again, but you must.
你不必再来，可是你执意要来。
2. have to多表示义务或习惯动作；
must则用于表示一种重要或急迫的事情。例如：
We have to care for the young.（义务）
She has to be at the office before eight every day. （习惯）
You must go to the manager at once, or you'll be dismissed.
务必马上去见经理，不然你会被开除的。（急迫的事情）
3. have to可用于不同的时态；
而must一般只用于现在时（但也可以表示将来的情况，在间接引语中也可以表示过去时）。例如：
I have to (must) leave now.
We'll have to buy another TV set.
They had to put off the sports meet because of the bad weather.
He said that the work must be finished within two weeks.
4. must还可以表示一种推断和揣测，而have to则不能。例如：
This must be Jin's pen.
There must be something wrong with the machine.
5. "must＋动词完成式"可以用来表示对过去情况的揣测，而have to则不能。例如：
She must have read the book sometime in the past, or she couldn't have answered the question so well.
她一定在过去某个时候读过这本书，不然，这个问题她不会回答得这么好的。
Note:
在现代英语中，have to 中不定式和疑问句式既可以按照助动词的变化规则构成，也可以按照行为动词的变化规则构成。例如：
Have you to finish the work before supper?
Do you have to finish the work before supper?
have got to 常可同have to换用，但有时表示不同的含义。比较：
He has to report to the headquarters every two days.（例行公事，习惯动作）
He has got to report to the headquarters every two days.（一道指示或命令，必得每天报告一次）
另外，作“有”解时，have got和have通常是可以换用的，have got更口语化，但有时表示不同的含义。比较：The man has a blind eye.那人有一只眼瞎了。
The man has got a blue eye.那人有一只眼被打青了。
must not表示禁止，是说话人强有力的劝告或命令，意为“一定要，不准”。因此，在回答由must引导的问题时，如果是否定的回答，表示“不必，没有必要”，不能用mustn't，而要用needn't
或don't have to.试比较：
You must not drive fast.你不能开快车。（路险或有速度限制）You needn't drive fast.（时间充裕）
You must not tell others.（警告）
You needn't tell others.（没有必要）
needs为副词，相当于necessarily, of necessity. must needs和needs must均可表示“必须，必定，不得不”，这层意义上可以通用；但must needs还可表示“偏偏，偏要”，含有讥讽、不满的意思，而needs must则一般无这层意思。例如：
I must needs go there now.
我现在非到那里去不可。（可用needs must）
Needs must when the devil drives.
情势所迫不得不那样。
She must needs go away when I want her.
我正需要她时，她偏偏离开了。（不可用needs must）
The telephone must needs ring when I went to bed.
我上床睡觉时偏偏有人来电话。（不可用needs must）
need指主语的主观特需情况而使之必要。need既可以作助动词，又可以作行为动词。作助动词时，need没有人称和数的变化，后接不带to的不定式（动词原形），否定式为needn't.作行动动词时，need同别的行为动词一样，有人称和数的变化，后接带to的不定式，否定式要在前面加don't（doesn't, didn't），疑问句用do (does, did) 提问。例如：
There need be no hurry, need there?
He need never know. (=He never needs to know.)
I need only add a few words. (= I only need to add a few words.)
比较：
Father sent me the book, so I didn't need to write to him for it.
父亲把那本书寄来了，所以我不必为此给他写信了。（信没写）Father sent me the book, so I needn't have written to him for it.
父亲把那本书寄来了，所以我本不该为此再写信给他的。（信已写）
She didn't need to come.她不必来的。（实际也没来）
She needn't have come.她本来不必来的。（但却来了）
Note:
作助动词用时，need只用于疑问句中和否定句中，在肯定句中常用must, have to, should, ought to等。例如：
Need you do it right now? I needn't, but he must.
She doesn't need to be told. She has already known it.
（客观情况使得告诉她没有必要：她已经知道）
She needn't be told. We should keep it secret from her.
（主观上不愿告诉）
1. ought没有词形变化，通用于所有人称，可以用于现在时，过去时和将来时，同带to的不定式连用，否定式为ought not to (oughtn't)，疑问式把ought放在主语前。例如：
He knew he ought not to tell her that.
Note:
ought to与must, have to, should的含义比较接近，但不完全相同。ought to表示义务或责任，用以提醒某人注意其义务，或提出劝告，指出一个正确、明智的行为。must强调的是主观愿望，指必须做什么，牵涉到说话人的权威。have to 则表示由某种情况、环境所迫而不得不做某事。should同ought to用法完全相同，只是ought to口气稍重一些。比较：
You ought to respect the old.（劝告）
You must do it at once.（含有说话人的权威性）
We'll have to reconsider the matter.（情况所迫：发现有新的问题）
We should (ought to) do more for the country.（义务，责任）
表示“必然”时，ought to的语气不像must那么肯定。
比较：
This is where the gold deposits must be.
这里一定是埋藏金子的地方。
This is where the gold deposits ought to be.
这里应是埋藏金子的地方。
used to +动词原形表示一种过去的习惯、过去的例行活动或方式，一个与现在情况相反的过去状况，意为“过去常常”，否定式为used not to (usedn't to)，疑问式把used放在主语前。be (become, get, grow) accustomed /used to ＋动名词或名词（不能加动词原形）意为“习惯于…，对…习惯”。例如：
He usedn't to like English, but he quite likes it now.
The students soon got used to school regulations.
She didn't use(d) to come.
She usedn't to come. 她过去不常来。
Did he used to get up early?
Used he to get up early? 他过去常早起吗？
Didn't he used to get up early?
Usedn't he to get up early? 他过去不是早起吗？
Note:
used to还可以同often, never, always连用。例如：He often used to work late at night.他过去常工作到深夜。
She always used to get up at four o'clock in the morning.
她过去总是早晨4点起床。
除在一般将来时中用于第一人称外，shall还有如下用法。
1.表示征求意见或请求指示。例如：
Shall we meet in the evening? 晚上见好吗？
How shall I start the machine? 怎样开动这部机器？
Note:
shall只表示“愿意按对方的指示去做”，而may, might或can 表示“征求对方的同意”，意为“行不行，好不好，可以不可以。”比较：
Shall I come in? 你要我进来吗？
May（或might, can）I come in? 我可以进来吗？
Shall I buy the dictionary? 要我买那本词典吗？
May （或might, can）I buy the dictionary?我可买那本词典吗？
Shall I go there tomorrow? 要我明天去那里吗？
May I go there tomorrow? 我明天去那里好吗？
用于第二、三人称，要重读，不可缩写、表示意图、意志、允诺、命令或必然结果等；但shall所表示的意志是说话人的意志，而非句子中主语的意志。在法律、条约、协定等文件中，shall 表示义务、规定等。例如：
You shall have a lot of money= I shall give you a lot of money. （意图）
你会有很多钱的。（我会给你很多钱的）
Each citizen shall carry his identification card when traveling.（规定）
旅行时每个公民务必带上身份证、
She shall get this paper in the evening.（允诺）
He shall get what he deserves.（警告）
Death is certain to all; all shall die. 物皆会死。（命运）
Better days shall soon follow.（预言）
will和would除在将来时态中用于第二、三人称外，还有如下用法。
1. 表示请求（这时will和would通用，而would更委婉，也用won't）。例如：
Will you give her the letter?
你把这封信给她好吗？
Would you please tell me your telephone number?
请把你的电话号码告诉我好吗？
2. 表示习惯或倾向。will用于一般的习惯，would用于描述过去的习惯或例行的活动。would同used to 强调过去的习惯性动作或状态，但如今已不存在，与现在的情况形成对比，既可表示过去持续的状态，也表示过去曾经的行为。例如：
Scarf used to be heavy smoker.
Father used not to be so forgetful.
would强调过去某种特定情况下的动作，是完全过去的事情，同现在没有联系。would 只表示重复的动作，不表示状态。比较：She used to get up at six in the morning.（正，重复的行为）
She would get up at six in the morning.（误）
Man used to think that the earth was flat.（正，持续状态）
Man would think that the earth was flat.（误）
would 可以表示不规则的习惯，used to则不可。
例如：
Sometimes she would take a walk in the neighboring woods.（不可用used to ）
An Englishman will show you the way in the street.
英国人在街上是会给你指路的。（英国人一般都会这样做。）In those days, whenever I had difficulties, I would go to Mr. Lees for help.
He used to get up at five, but now he gets up at six.
下面两句是错误的，应改用used to:
He would be very nervous when taking an exam.
Before liberation, workers would work sixteen hours a day.
3. 表示推测。例如：
It will be Mr. Wang knocking at the door.
It would be about ten o'clock when he left home.
They will have arrived in New York by now.
Note:
will表示推测时没有must把握大，should也可以表示推测，但比will 把握略小。其程度由低到高为might→may→could→should→ought to→would→will→must。
4. 表示命令、强迫等（只用will，通用于所有人称）。例如：
All will arrive before 7:45.
所有人员务必在7:45之前到达。
I won't allow her to do that.
我不会让她做那件事的。
5. 表示意愿或固执坚持。用于非人主语时，表示固有性质、倾向。
例如：
She won't lend me the money.
她不愿把钱借给我。
He is the man who will go his own way.
他是一个自行其是的人。
The window won't open.
窗子打不开。
I won't argue with you.
比较：
He will do it, whatever might happen.
不管发生什么，他都要做这件事。（主语He坚持要做）
He shall do it, whatever might happen.
不管发生什么，他都必须做这件事。（我们坚持要He做）
6. 表示能力（拟人化）。例如：
The hall will seat 1000 people.
That was a strong dog. How much would it carry?
7. 表示客观事实。例如：
Fish will die out of water.
Oil will float on water.
8. 表示意图或允诺。例如：
I'll trouble you for the dictionary.
You will have your share.
I won't let you down.
9. 表示拒绝，用won't 。例如：
I won't listen to your nonsense.
I urged him to do it, but he wouldn't hear of it.
10.will在if从句中的运用。
在含有if从句的主从复合句中，如果if引导的条件状语从句表示的是一般将来时或过去将来时，不可用will或would，而要用一般现在时或一般过去时代替。但是，will可用于if从句中表示各种“愿望”，这些愿望包括“请求，意愿，拒绝，同意，允许，能够，坚持，选择，计划”等。例如：
If you will come into the hall, the meeting will begin soon.
请到大厅里来，会议快要开始了。（请求）
If you will make another try. I shall do everything possible to help you.
如果你原意再试一次的话，我愿尽一切可能帮助你。（意愿）If he won't go with you, I shall ask somebody else.
如果他不肯同你一起去的话，我将另找他人。（拒绝）
If you will agree with me. I shall tell you everything about it.
如果你同意我的观点，我将把一切都告诉你。（同意）
If you will not come late again, I shall let you in.
如果你答应不再迟到的话，我就让你进去。（允诺）
If anyone will find a cure to the disease, it will be a wonder.
如果有人能够治好这种病的话，那将是一个奇迹。（能够）
If you will do it like that, you will fail.
如果你坚持要那样做的话，你会失败的、（坚持）
If you will buy bread, I shall buy beer.
如果你买面包，我就买啤酒。（选择）
If you won't lend money to him, please let me know.
如果你不打算把钱借他的话，就让我知道。（计划）
Note:
在下面的句子中，would有“可能”的含义：
I wouldn't dream of it.我做梦也不会想到。
That's what he would do.他会那么做的。
You wouldn't know.你不会知道的。
CAN
指人体力、智力、性格上的主观可能，也指性质上可能．
1.表示许可。can表示许可时，是may在非正式场合的替代词。例如：
You can borrow two books at a time from the library.
2.表示可能性。例如：
I can't guess whose book it is.
Measles can be quite dangerous.
3.表示能力。can表示能力时（即有某种知识和技能而能办到），可与be able to换用，但在将来时和完成时中必须用be able to结构；表示经过努力而成功地办到了某个具体的事情时，只能用be able to, 不可用can.这种用法的be able to相当于succeed in 或manage to.例如：
Can you type?
Are you able to type?
He could swim across the river even in his later years.
He was able to swim across the river even in his later years.
He was able to swim across the river when the boat sank.
I'm sure we shall be able to get you a job soon.（不可用can）
He has been able to finish the work on time.（不可用can）
After years of hard work he was able to win the prize.（不可用could）
She couldn't climb the mountain.（没有能力爬，因而也没爬）She was not able to climb the mountain.（尝试爬过，但没能爬上去）
Note:
could是can的过去式，除具有can的各种功能外，还可以用来比较委婉、客气地提出问题或陈述看法。例如：Could you come a little earlier?
I am sorry I couldn't lend you the book now.
can和could还可以表示某人或某物一时的特点。例如：
It can be very misty in this area.这个地区有时会大雾弥漫。
He can be very friendly at times.他有时会很友好。（并不是一贯友好）
can / could + have + 过去分词有时相当于may / might＋have + 过去分词，意为“可能”。can是could 的口语体，语气上较婉转。can not have + 过去分词和could not have + 过去分词均可表示“过去不可能”。例如：
John can / could have been seriously hurt in the accident.
Can they have missed the train?
He couldn't have been swimming all day.
肯定的推测用must,否定的推测用can not。比较：What she says must be true.
What she says can not be true.
can be和could be后可接possible作表语。例如：
Can it be possible?
It can't be possible.
Could it be possible that he dialed a wrong number?
possible的副词形式possibly也可同can或could连用，表示强调。
例如：
I can't possibly do it. It's against the law.
1.表示许可（正式场合）。例如：
You may take the book home.
Candidates may not bring reference books into the examination room.
（表示说话人不许可，相当于We don't permit…）
2.表示可以做或可能发生的事。例如：
They may not be there today.
A situation like this may / can occur from time to time.
3.表示祝愿。例如：
May your kingdom come!
May our friendship live long.
4.用在表示目的的状语从句中。例如：
Get up early so that we may catch the train.
比较：
They may not go swimming.（不许可）
They may not come if it rains.如果下雨，他们就可能不来。
They mustn't go swimming.他们一定不能去游泳。（责令不得去）
Note:
might是may的过去式，在表示“可能”这个概念时，may和might 是可以换用的，但might表示较多的怀疑，可能性较小，或者表示更婉转的语气。试比较：
Jim may lend you the money.（可能性较大）
Jim might lend you the money.（可能性较小）
Might I ask a question?（较婉转）
回答May I …?问句时，may not意为“不可以”；回答Can…？问句时，may not意为“可能不”；may not还可以表示“可以不”例如：
May I sit here? No, you may not.
Can the story be true? It may be, or may not be.可能是，也可能不是。
You may not tell her that.你可以不把那件事告诉她。（也可以表示：你不可把那件事告诉她）。
may表示“可能”时一般不用在疑问句中，而以be likely to等结构替代。例如：
Is he likely to win the match?
他有可能会赢这场比赛吗？
这种结构用来建议或劝说某人采取某种行动，相当于had better.
例如：
It is very late, so you may / might as well go to bed.
夜深了，还是去睡吧。
May well+动词原形意为“理应，有足够的理由”。
例如：
He may well be proud of his son. 他大可以他的儿子为荣。
She may well say so.她说得对。
1.用于疑问句或感叹句中（表示意外、惊讶等，与how, why, who连用）。
例如：
How should I know?
Why should you be worrying?
Who should come to meet us but the manager!
Why was it that the manager would go back on his words?
2.用在某些状语从句中。例如：
He took a taxi to the station so that she should not miss the train.（也可根据需要，用might 或could）
They removed and buried all machines for fear (that) the enemy should make use of them.
3.用在I'm surprised, It worries me, It's a pity, It's unthinkable等结构后面的句子中表示惊讶、忧虑、惋惜、欢欣等情绪。例如：I'm surprised that he should eat so little every day.
他每天吃得那么少，真使我感到惊讶。
It's a pity that she should fail in the entrance examination.
她没有考取，真是可惜。
4.表示应该做，且有一种道义上的责任。例如：
I should help him because he is in trouble now.
You should do it because you have promised to.
比较：
would常用来解释为什么没做某事。例如：
I would go to the football match but the weather is too bad. So I won't.
I would do it but I have something too urgent to be delayed.
5.意为“可能，该”，表示对现在情况、将来情况或过去情况的某种推测。例如：
He should arrive at noon.他该在中午到达。
Jim should be at home.吉姆可能在家。
He should be taking a bath now.他可能正在洗澡。
They should have finished the work by tomorrow.
到明天他们就可能完成工作了。
They should have reached the town by now.
他们现在该已经到达那座小城了。
dare表示意志上的主观可能，指在勇气、胆量上可能。dare既可用作助动词，又可用作行为动词。作助动词用时，dare 的否定式为dare not,后接动词原形；作行为动词用时，dare的否定式是don't (doesn't. didn't) dare，后接带to的动词不定式。
例如：
She dare not (daren't) go out at night.
(= She doesn't dare to go out at night.)
He dares to say what he thinks.
Dare you touch it again?
Note:
dare＋动词原形表示现在或将来时间，dare后也可以接动词完成式指过去的情况。例如：
Dare he have done it yesterday?
dare作行为动词用时，后接的不定式也可省略to。
例如：
She has never dared (to) tell her mother that.
How dare you (he)…?表示“愤怒、谴责”之意，不表示疑问。
例如：
How dare you call him a liar?
你怎敢把他说成是撒谎者？
dare作及物动词时用时，有“挑激”之意。
例如：
I dare him to jump over the wall. 我挑激他跳过那堵墙。
I dare say为惯用语，意为“我想，我以为”。例如：
She will keep her word, I dare say.我想她会守信用的。
情态助动词+ 完成体
1. may和might ＋动词完成式
此结构用于推测过去的行为。例如：
She said that he might have missed the plane.她说他可能误了航班。
If we had taken the other road, we might have arrived earlier.
2. can和could + 动词完成式
A. 表示过去能做而没做的事，有一种对过去未付诸实施的事情的惋惜。例如：
In those circumstances we could have done better.
在那样的情况下，我们本来可以做得更好的。（但没有做得更好）
B. 推测过去的某种行动。
Where can /could she have gone? 她可能到哪里去了呢？
The boy can't have finished reading the book so soon because it is difficult even to an adult.
这孩子不可能那么快就把这本书读完的，因为即使对一个成人来说，这本书也是相当难的。
Note:
can't和couldn't＋动词原形可以用来表示否定推断。例如：He can't be over fifty.他不可能超过50岁。
3. must ＋动词完成式
表示对过去行为的推断，具有较大的可能性，意为“一定…，想必…”。例如：
She must have gone through a lot.
她一定吃过很多苦。
Note:
must＋动词原形→对现在的推测，must be＋现在分词→对未来或现在正在进行的推测。例如：
She looks happy; she must be having a good time.
It must be raining tomorrow according to the radio.
4. needn't＋动词完成式和didn't need to do.
A. needn't＋动词完成式表示一种已经做过的但并无必要的行
为。例如：
You needn't have watered the flowers, for it is going to rain.
你本来不必浇花的，因为天要下雨了。（但却浇了）
We needn't have told him the news because he knew it already.
B. didn't need (have) to do结构表示没有必要做某事，实际上也没有做。例如：
I didn't need to clean the windows. My sister did it.
我不必擦窗，我妹妹擦了。（我没有擦）
We didn't need to carry his luggage; his brother carried it himself.
5. should + 动词完成式
A.此结构的肯定式表示应该做的事而没有做，否定式表示某种行为不该发生但却发生了。例如：
You should have given her more help.
你应该多给她一些帮助的。（但没有给）
She shouldn't have left the hospital so soon, for she had not yet recovered.
她本不该那么早就离开医院的，因为她还没有康复。（但离开了）
B. 表示推测，意为“可能”，但可能性较小。例如：
He should have finished the work by now.
他现在该把工作完成了。（推测）
I think they should have arrived by this time.
我想他们现在该到了。
C. should / would have thought意为“本以为，本认为”。例如：
A: "Can you type?"
B: "Certainly."
A: "Well, I should have thought you wouldn't."
I should have thought she wouldn't agree.
我本来认为她不会同意的。
D. should have thought有时意为“认为，以为”，相当于should
think，但表示更为委婉、谦逊或不肯定的语气。例如：
I should have thought it fairly good.
我以为它是很不错的。
I should have thought you might take this into consideration.
我认为你要把这个考虑进去。
E. should have ＋过去分词用于虚拟语气：
Had you written him, you should have known the details.
6. ought to + 动词完成式
此结构表示某种过去应该做而没有做的事，或被忽略未做的某种明智行为。例如：
You ought to have returned the book earlier.（还晚了）
You ought to have refused her at the beginning, but now it is too late.
Note:
这里的ought to也可以用should代替。
比较：
Can / Could he have read the book? 他可能读过那本书吗？
He may / might have read the book. 他也许读过那本书。
He should（ought to ）have read the book. 他应该读过那本书。
He must have read the book. 他一定读过那本书。
He can't have read the book. 他不可能（决不会）读过那本书。
这两种结构表示：“应当正在…，可能正在…”，“应当一直在…，可能一直在…”等。
例如：
She might be still thinking of you.
她可能一直在想你。
He must have been working hard these years.
这些年来他一定是非常努力的。
比较→
对现在活动的推测：
What can / could she be doing now? 她现在会在做什么呢？She may / might be watering the flowers. 她可能在浇花。She must be watering the flowers. 她一定在浇花。
She can't be watering the flowers.她不可能在浇花。
比较→
对一直进行的活动的推测：
He may have been writing the paper for months.
他也许几个月来一直在写论文。
He must have been writing the paper for months.
他肯定几个月来一直在写论文。
Can he have been writing the paper for months?
难道他几个月来一直在写论文吗？
英语语法-助动词和情态动词用法及习题
目录 1助动词和情态动词的定义 (2) 2 can，may，must (3) 3 Will you～？和Shall I（we）～？ (10) 4 would和should (14) 5 have to (16) 练习题 (17) 答案 (18)
1助动词和情态动词的定义 在英语中，助动词一般没有词义，主要帮助构成谓语，表示时态、语态或构成疑问及否定形式。对于助动词，同学们一般了解即可。 情态动词与助动词不同，它有词义，但它也和助动词一样，不能单独作谓语，它必须和其他动词一起构成谓语，另外重要的一点是情态动词没有人称和数的变化；情态动词后必须跟动词原形。 （×）She cans swim well. （×）She can swims well. （○）She can swim well. （○）She swims well. 即使主语是第三人称单数（例如she）can也不能加“s”。 句子中有情态动词can时，即使主语是第三人称单数，也不能在一般动词（例如swim）上加“s”。 1 助动词的种类 1.be（am，are，is，was，were，been，being） 它与现在分词结合，可以构成进行时态（参见第九章），与过去分词结合可以构成被动语态（参见第十三章）。 I am reading the book.我正在读这本书。 The book was written by me. 这本书是我写的。 2. have（has，had，having） 它与过去分词结合，构成完成时态（参见第十一章）。 I have finished my homework. 我已经写完作业了。 3.shall（should），will（would）
助动词和情态动词
助动词和情态动词 1. ---Good morning. I've got an appointment with Miss Smith in the Personnel Department. ---Ah, good morning. You______ be Mrs. Peters. （10北京） A. might B. must C. would D. can 2. I have told you the truth. ______ I keep repeating it? （10江西） A. Must B Can C May D Will 3. Jack described his father, who _______a brave boy many years ago, as a strong–willed man （10安徽） A. would be B. would have been C. must be D. must have been 4. I_______ have watched that movie —it’ll give me horrible dreams. （10山东） A. shouldn’t B. needn’t C. couldn’t D. mustn’t 5. Doctors say that exercise is important for health, but it _______ be regular exercise. （10辽宁） A．can B．will C．must D．may 6．Wine ____ do good to people’s health if drunk properly. A. can B. should C. must D. might 7. But for the help of my English teacher, I ____ the first prize in the English Writing Competition. A. would not win B. would not have won C. would win D. would have won 8. My sister met him at the Grand Theatre yesterday afternoon, so he _____ your lecture. A. couldn’t have attended B. needn’t attend C. mustn’t have attended D. can’t attend 9. ---Has Mr. Tom White arrived? ---Yes, already. ____ he wait outside or just come in? A. Shall B. May C. Could D. Must 10. Walking in space ____ sound easy, yet great care and skills are needed. A. should B. shall C. may D. must 11. ---Amazing! You ____ wear slippers at work! ----Don’t you know it’s a fashion? A. must B. should C. can D. may 12. ---The two astronauts had been trained for long before they flew to space. ---Oh, they ____ quite a lot of difficulties. A. might go through B. may go through C. should have gone through D. must have gone through 13. ---Can I pay the bill by check? ---Sorry, sir. But it is the management rule of our hotel that payment ____ be paid in cash. A. will B. can C. should D. shall 14. ---Catherine looks sad. Did you tell her about the accident? ---Yes, but I ____ her just before her final exams.
be动词、助动词、情态动词讲解(基础篇)第一讲
be 动词、助动词、情态动词讲解（基础篇） 1、 用单数，反之用复数。 ◆ 句中含有be动词时： 肯定句：主语＋be ＋其他 否定句：主语＋be ＋not ＋其他 一般疑问句：Be ＋主语＋其他＋？ 特殊疑问句：疑问词(what / who / when / where)＋be ＋主语＋其 他＋？ I am a teacher. You are right. She is 16 years old. My father is at home. The students are playing games. My teacher was ill yesterday. There is a picture on the wall. There are two books on the table. ★ be 动词用法歌： 我用am，你用are，is 连接他她它。单数名词用is，复数名词全用are。 变疑问，往前提，句末问号莫丢弃；变否定，更容易，be 后not 莫忘记； 疑问否定任你变，句首大写莫迟疑。 ★ be 动词作谓语，它后面一般跟名词、形容词或介词短语。她个子很高。 她在教室里。她是一个高个子的女孩。 2、助动词的用法。 英语句子按正常语序是“什么人或事物” + “做什么”，即，我们常说的“主语+ 谓语+ 其他” 。 ①主语为I 或复数名词、代词时：肯定句：I / We / They / The students
＋动词原形＋其他＋。 We watch TV every night. 变否定：主语＋don't ＋动词原形＋其他＋。 We don't watch TV every night. 一般疑问句Do + 主语+ 动词原形+ 其他+ ？ Do you watch TV every night? Yes, we do. / No, we don 't. 特殊疑问句：疑问词+ do + 主语+ 动词原形+ 其他+ ？ How often do you watch TV? ②主语为单数名词或代词时：肯定句：主语+ 动词第三人称单数形式 + 其他+ 。 He watches TV every night. 否定句：主语+ doesn't+动词原形+其他+。 He doesn't watch TV every night. 一般疑问句：Does + 主语+ 动词原形+ 其他+ ？ Does he watch TV every night? Yes, he does. / No, he doesn 't. 特殊疑问句：疑问词+ does + 主语+ 动词原形+ 其他+ ？ How often does he watch TV? ★主语为单数或不可数名词，谓语要用单数第三人称，反过来，看见动词用了单数第三人称，可以推知主语是单数或不可数名词。 ( )1. How __ ______ your dad help at home? A. do B. does C. is ( )2. ______ goes bad easily in summer. A. Milk B Apples C. Cakes ③过去时的句式（当句子时态为过去时时，动词用过去式，不受主语单复数的影响） 肯定句：主语+ 过去式+ 其他+ 。 He / We got up early every morning last year. 否定句：主语+ didn't + 动词原形+ 其他+ 。 He / We didn't get up early every morning last year. 一般疑问句：Did + 主语+ 动词原形+ 其他+ ？ Did he / you get up early every morning last year? Yes, he
情态动词与虚拟语气
情态动词与虚拟语气 【语法要点】 情态动词 所谓情态动词是指它含有一定的含义，可以表达某种感情和说话的语气，但是它不可以单独使用 作谓语动词。学习情态动词主要学习英语国家的语言习惯和表达法，特别是在口语中不要过分追求原理，更不要不根据说话场合而进行推理，编造出一些语法结构正确的中文式英语。 一、情态动词的类型 1.只作情态动词的有：must、can、could、may、might、ought to 2.既可作情态动词又可作实义动词的有：need、dare 3.既可作情态动词又可作助动词的有：shall、should、will、would 二、情态动词的特征 1.表示说话人的情感态度，不能单独作谓语，与行为动词或连系动词一起作谓语。 2.情态动词没有人称和数的变化，后接动词原形。 3.具有助动词的特征：可用来构成否定句、疑问句或简短答语。 三、情态动词的用法 1.表示能力 （1）表示现在的能力，用can 或be able to。表示一般的能力时多用can，表示“经过努力成功 的做成某事”用be able to。 （2）表示过去的能力，用could或was/were be able to。区别同上。 （3）表示将来的能力，用will be able to。 2.表示推测、可能性 （1）can 用在肯定句中表示客观的可能性，而不表示具体事情实际发生的可能性。 例如：Accidents can happy on such rainy days. （2）表示具体事情实际发生的可能性的情态动词，其表示可能性的层次如下表： 情态动词肯定式否定式疑问式 must 必定、必然、一定 will 很可能、大概不会、不该会,,吗？ would 可能性较will 小不会、不该（较won’t 弱）会,,吗？（较will 弱） should 应该会、理应（表示合乎理想的情况或结果） ought to 与should 同义 can 一定不会、不可能（否定推测）有可能吗？ could 可疑的可能不可能（与can’t 同义）有可能吗？（较can 弱）may 或许、可能、说不定可能不 might 或许、可能（较may 弱）可能不（较may not 弱） 注意→（1）may，must 常用于肯定句，一般不用于否定句和疑问句。 （2）can 常用于否定句，疑问句和感叹句中，表示疑惑、惊讶或不相信等意思。could 既可用于肯定句，又可用于否定句、疑问句中。
英语助动词和情态动词及练习
英语助动词和情态动词及练习 一、概述 不同的时态（一般式、进形式、完成式、将来式），不同的语态（主动、被动），不同的语气（祈使、陈述、虚拟），不同的结构（肯定、否定、疑问），以及说话者本身的态度或命令、请求、愿望、可能等，所有这些都要借助于助动词和情态动词表达出来。助动词一般没有词意，不能单独作谓语动词，除非省略句中。他们只参加时态、语态、语气或否定、疑问结构。情态动词有词义，可以用来表示说话者的语气和态度。主要的助动词和情态动词如下表： 二、助动词 助动词一般没有词意，不能单独作谓语动词。其作用在于帮助构成各种时态、语态、否定、疑问等。 1、助动词be（am, is, are, was, were, being, been）的用法 （1） be后跟现在分词构成进行时态。 Who is playing the violin?谁在拉小提琴？ She was reading a book then.那时她正在读书。 （2）be后跟过去分词构成被动语态。 He was asked to do the work.有人要他干这件工作。 You are invited to attend the meetintg.有人邀请你参加会议。 （3）be 后跟不定式作谓语，有如下几种情况： ①表示计划、安排将要发生的事。 Who are we to meet?我们要见谁呀？ I'm to have supper with John this afternoon.今天下午我要与约翰一起吃晚饭。 ②表示指示、命令，否定式表禁止。 You are to see the headmaster today.今天你必须去见校长。 You are not to enter the room without permission.未经允许你不能进入房间。 ③表示义务、责任等，同should。 You are to be back before 5.你得在5点钟以前回来。 What is to be done?该干什么。 ④表示可能性，与情态动词may, can同义。 Such books are to be found in any library.这种书任何图书馆都有。 Not a sound was to be heard.一点声响也没有。 ⑤表示后来发生的事，可以用来表示命运或注定 They say good-bye, little knowing that they were never to meet again.他们告别了，没想到再也不能相见了。 He was to regret the decision.他有一天会后悔做出这一决定的。 ⑥用于习语 Where am I to go? 我该向何处去？ What am I to do? 我该怎么办？ 2、助动词have(has, had, having)的用法 （1）助动词have可以构成完成时或完成进行时
be动词-情态动词及助动词用法
七年级英语双休日作业 班级：姓名：等级 英语句型变化总结练习 1、含有be动词am，is，are构成的句子： 变一般疑问句时把am，is，are提到句子的前面，句尾用问号即可。 变否定句时直接在am，is，are后面加not即可。例如： 肯定句:He is a student. 一般疑问句: a student? 否定句: He a student. 肯定句：We are from China. 一般疑问句: from China? 否定句：We from China 2. 由情态动词can, may, should等构成的句子: 变一般疑问句时把can, may,提到句子的前面,句尾用问号即可. 变否定句时直接在can, may,后面加not即可. 例如: 肯定句: She can swim. 一般疑问句:she swim? 否定句: She swim. 3. 由行为动词构成的句子: 需要加助词do或does. 变一般疑问句时把do/does放在句子前面. 变否定句时在主语后面加don’t / doesn’t , 谓语用动词原形。例如: 肯定句: They play football after school. 一般疑问句: play football after school? 否定句: They football after school. 肯定句：Tom watches TV every day. 一般疑问句: Tom TV every day? 否定句: Tom TV every day.
注意：变否定句时相关词的改变 肯定句变否定句时，除将谓语变为否定式外，句中其他词语也可能随之改变： 如将some改为any，too和also改为either，and改为or等：There are some birds in the tree. 树上有些鸟。 →There aren’t ______ birds in the tree. 树上没有鸟。 He likes the book, too. 他也喜欢这本书。 →He doesn’t like the book, ______. 他也不喜欢这本书。He likes singing and dancing. 他喜欢唱歌和跳舞。 →He doe sn’t like singing ______dancing. 他不喜欢唱歌也 不喜欢跳舞。补充练习： 根据句后括号内的要求，填入句中所缺的词： 1. I know the answer. (一般疑问句) ______ ______ know the answer? 2. We can see some birds. (一般疑问句) ______ ______ see ______ birds? 3. There is a computer in the house. (一般疑问句) ______ ______ a computer in the house? 4. There are some flowers on the teachers’ desk. (一般疑问句) ______ ______ any flowers on the teachers’ desk? 5. There are some apples on the tree. (否定式) There ______ ______ ______ apples on the tree. 6. I think he is old. (否定句) I ______ think he ______ old.
be动词、助动词、情态动词讲解(基础篇)Microsoft Word 文档
be动词、助动词、情态动词讲解 (基础篇) 1、be动词的用法。 英语中，be动词选用单数还是复数，要由主语来定，主语是单数，就用单数，反之用复数。 ◆句中含有be动词时： 肯定句：主语＋be ＋其他 否定句：主语＋ be ＋ not ＋其他 一般疑问句： Be ＋主语＋其他＋？ 特殊疑问句：疑问词（what / who / when / where）＋ be ＋主语＋其他＋？ I am a teacher. You are right. She is 16 years old. My father is at home. The students are playing games. My teacher was ill yesterday. There is a picture on the wall. There are two books on the table. ★ be动词用法歌： 我用am，你用are，is 连接他她它。单数名词用is，复数名词全用are。 变疑问，往前提，句末问号莫丢弃；变否定，更容易，be后not莫忘记； 疑问否定任你变，句首大写莫迟疑。 ★ be动词作谓语，它后面一般跟名词、形容词或介词短语。 她个子很高。她在教室里。 她是一个高个子的女孩。 2、助动词的用法。 英语句子按正常语序是“什么人或事物” + “做什么”，即，我们常说的“主语 + 谓语 + 其他”。 ①主语为I 或复数名词、代词时： 肯定句： I / We / They / The students ＋动词原形＋其他＋。 We watch TV every night. 变否定：主语＋ don’t ＋动词原形＋其他＋。 We don’t watch TV every night. 一般疑问句 Do + 主语 + 动词原形 + 其他 + ？ Do you watch TV every night? Yes, we do. / No, we don’t. 特殊疑问句：疑问词 + do + 主语 + 动词原形 + 其他 + ？ How often do you watch TV?
助动词与情态动词-讲解及练习测试题
助动词与情态动词 一、助动词 助动词有be, have, do, will, shall。它们本身没有词义，只和实义动词的一定形式构成复合谓语，用来表示时态和语态，构成否定、疑问及加强语气等。 1、be (am, is, are, were, been) （l）“be + -ing”构成进行时态； （2）“be + 过去分词”构成被动语态； （3）“be + 动词不定式”构成复合谓语： ①表按计划安排要发生的事。The prime minister is to visit Japan next year.总理将于明年访问日本。 ? “do + 动 只有 (1)表示能力，如：He can speak English better than you. (2)在疑问句和否定句中表示“怀疑”、“猜测”或“可能性”，如：Can this green bike be Liu Dong's? (3)表示“许可”时can可以和may换用，如：You can (may) go home now. (4)如果要表示语气婉转，可用could代替can，这时could不再是can的过去式，如：Could you come again tomorrow? (5)can和be able to都可表示能力，两者在意思上没有什么区别。但是can只能有现在式和过去式，而be able to 则有更多的形式，如：He will be able to do the work better. 2、may和might (might为may的过去式)的基本用法 （1）表示允许或征询对方许可，有“可以”之意， 如：You may use my dictionary. 在回答对方说“可以做某事”或“不可以做某事”时，一般多不用may或may not，以避免语气生硬或不容气。而用比较婉转的说法进行回答。如：---- May I use this dictionary? ---- Yes, please. 或---- Certainly. 在请求对方许可时，如果Might I…? 就比用May I…? 语气更婉转些，如：May I have a look at your new
(助动词情态动词)练习
专四语法练习2 助动词、情态动词 1. It’s wonderful that you ___C___ have achieved so much in these years. a. may b. can c. should d. would 2. He ___D___ hardly say anything more, since you know about it. a. don’t need to b. needn’t c. needs d. need 3. You __B____ the look on his face when he won the prize. a. would have seen b. should have seen c. must see d. can be seeing 4. Some people think the stock market will crash, but ___B___. a. I wonder if it happens b. I doubt if it will happen c. I am afraid it wouldn’t happen d. I doubt if it does happen 5. “Whatever has happened to George?” “I don’t know. He _B_____ lost.” a. can have got b. may have got c. might get d. could get 6. He has no idea what the book is about. He ___B___read the book.
中考英语情态动词、助动词、系动词专项讲解
中考英语情态动词、助动词、系动词专项讲解 中考英语情态动词、助动词、系动词专项讲解 语法精讲 1.can 和could 2.may 和might 3.need, must和have to 情态动词 4. should和ought to 5. shall, will和would 6. had better 1.can和coul d ① can表示能力，意为“能够，可以”，could用于过去时， 例如He can finish his homework al one. 他可以单独完成作业的。 He couldn’t cook when he was 18 years old. 他18岁时还不会做饭。 ② can表示推测，意为“可能”，在否定句中表示否定的猜测，意为“不可能”，could用于对过去的猜测，can’t be 不可能 例如：He could be cooking at this time yesterday. 他昨天这个时候有可能正在做饭。 He can’t be here be cause he has gone to American.他不可能会在这里，因为他已经去美国了。 ③ can表示请求语气，coul d的语气更委婉， 例如：Can I help you? / Coul d I help you? 有什么我可以为您效吗？ 拓展：be abl e to=can也为“能够”，用来表示能力（有人称和时态的变化） 例如：He is able to d eal with this problem. 他能解决这个问题的。 2.may和 might
① may表示请求，might语气更委婉， 例如：May I help you? Might I sit here? ② may表示肯定的推测，语气比can更弱，might对过去的推测 例如：Mary may be doing her homework now. May can be doing her homework now. can表达的推测语气比may更强，更有把握。 3. must和have to ①must表示命令、责任，意为“一定，必须”，must not/ mustn’t表禁止，“一定不要”， 例如：Children must stay away from strangers.孩子一定要远离陌生人。 You mustn’t play fire because it’s dangerous. 千万不要玩火，因为太危险了。 拓展：在表示禁止时，会用“No Doing”来表示，如No Smoking. / No Walking.等。 ② must表示推测，语气比can更强. 例如：Mr. Liu must be on holiday now because he is wearing pants. 刘老师现在肯定在度假因为他正穿着平底裤呢！（上课是要穿正装的） ③ Must作一般疑问句开头提问时：肯定用must回答，否定用needn’t或d on’t have to回答。 例如：Must I finish my homework now? Yes, you must. / No, you ne edn’t. ④ must 和have to 的区别： a) must没有人称、时态的变化，而have to根据人称、时态的变化，有不同的形式。 b) Must表示主观上必须做，而have to 表示客观需要。
助动词与情态动词练习题.docx
1.If they _____ to do this work, he might do it some other way. A. were B. should C. will D. can A. should have sent B. were going to send C. should be sending D. should send 3.Let's take a walk, ____? A. will we B. don't we C. do we D. shall we 4.He was a good swimmer so he _____ swim to the river bank when the boat sank. A.could B.might C.should D.was able to 5.I went to the doctor's yesterday, I had to wait for half an hour before he ____ see me.
A.can B.may C.might D.could 6.---- _____ this book be yours? ---- No, it ____ not be mine. It ____ be his. A. Can, must, may B. May, might, must C. Can, may, must D. Must, can, may 7."We didn't see him at the lecture yesterday. " "He _____ it. " A. mustn't attend B. can't have attended C. would have not attended D. need have attended A. can have missed B. may have missed C. can have lost D. may have lost 9.Since the ground is white, it _____ last night. A. had snowed B. must have snowed
中考考点情态动词和助动词
Period Ten 情态动词和助动词 重点掌握情态动词can, may, must, need等词在语境中的运用，情态动词在句子中常用来表示“能力，允许，禁止，意愿，可能”等情感或态度。掌握助动词do, will, shall, have, be在句中的作用。 一、情态动词 1. 情态动词的定义 情态动词表示说话人对所述动作或状态的态度或看法。情态动词本身有词义，但不能独立作谓语，必须和动词一起构成谓语，在各种人称后都用同样的形式。 2. 情态动词的用法 (1)can的用法 ①表示人或物本身所具有的能力，意为“能，能够，会”。eg: Can you skate? 你会滑冰吗？ She can speak a little Chinese. 她能讲一点儿汉语。 ②表示可能性，意为“可能会”，常用于否定句或疑问句。eg: Can it be true? 那会是真的吗？ That can’t be Mary; she’s in hospital. 那不可能是玛丽；她住院了。 (2) could的用法 ①could可以表示过去的能力，若表示现在的能力时，语气比can委婉。eg: She couldn’t swim half a year ago. 她半年前不会游泳。 What a good idea! Maybe I could talk about English names. 你的想法太好！也许我能谈谈英国人的名字问题。 ②表示礼貌，常用在疑问句中，意为“能，可以”，答语一般用can。 —Could I borrow your bicycle? 我可以借一下你的自行车吗？ —Yes, you can./ No, you can’t. 是的，可以。/不，不行。 ③表示猜测、怀疑等态度，一般用于否定句、疑问句或感叹句中。对现在情况表示猜测时，could 比can更 不确定，其结构为“can/could+动词原形”；对过去表示猜测时，结构为“can/could+ have+过去分词”。eg: You could be right, I suppose.我想可能是你对。 Don’t worry. They could have just forgotten to phone. 别担心。他们很可能只是忘了打电话。 (3) may和might的用法 ①表示允许，用于肯定句。eg: You may come if you wish. 你要来就来吧。 Passenges may cross by the footbridge. 乘客可使用步行桥。 ②表示许可，用于疑问句。might是may 的过去式，比may语气委婉。eg: May I come in? 我可以进来吗？ Might I make a suggestion ? 我可以提个建议吗？ ③表示客观不可能性。eg: Take an umbrella with you. It may rain. 带上雨伞，可能会下雨。 (4) must的用法 ①must表示“必须”时多用于肯定句或疑问句，其否定回答用needn’t；，用于否定句时，表示“不应该，不 许可，不准，禁止”。eg: I must go to the bank to get some money. 我得到银行去取些钱。 Cars mustn’t park in front of the entrance. 入口处不得停放汽车。 ②它在肯定句中，还可表示“推测”，意为“一定”。“must be”表示对现在某事的推测；“must have done” 表示对过去的推测；反意疑问时，要根据must后的be或have来做。eg:
情态动词的用法完整详细
情态动词 定义: 情态动词是一种本身有一定的词义,但要与动词原形一起使用，给谓语动词增添情态色彩，表示说话人对有关行为或事物的态度和看法，认为其可能、应该或必要等。 情态动词后面加动词原形。 分类： 情态动词有四类： ①只做情态动词：must,can(could),may(might),ought to ②可做情态动词又可做实义动词：need,dare ③可做情态动词又可做助动词：shall(should),will(would) ④具有情态动词特征：have(had) to,used to 位置: 情态动词在句中放在谓语动词之前, 谓语动词前若有助动词,则在助动词之前,疑问句中, 情态动词 则在主语之前。 I can see you. Come here. 我能看见你，过来吧。 He must have been away. 他一定走了。 What can I do for you? 我能帮你吗？ How dare you treat us like that！ 你怎能那样对待我们！ 特点: 情态动词无人称和数的变化, 情态动词后面跟的动词需用原形,否定式构成是在情态动词后面加"not"。个别情态动词有现在式和过去式两种形式, 过去式用来表达更加客气, 委婉的语气, 时态性不强, 可用于过去，现在或将来。情态动词属非及物动词，故没有被动语态。情态动词没有非谓语形式，即没有不定式，分词，等形式。 He could be here soon. 他很快就来。 We can't carry the heavy box. 我们搬不动那箱子。 I'm sorry I can't help you. 对不起，我帮不上你。 基本助动词与情态助动词最主要的区别之一是，基本助动词本身没有词义，而情态助动词则有自己的词义，能表示说话人对有关动作或状态的看法，或表示主观设想： What have you been doing since? （构成完成进行体，本身无词义） I am afraid I must be going. （一定要） You may have read some account of the matter. （或许已经） 除此之外，情态助动词还有如下词法和句法特征：
系动词助动词情态动词
系动词助动词情态动词内部编号：（YUUT-TBBY-MMUT-URRUY-UOOY-DBUYI-0128）
系动词、助动词、情态动词 一、情态动词 1.can(could):能够、可能、可以；may(might):可以、可能；must:必须； shall:将会；should:应该；will:将会，愿意；would:将会 2.半情态动词(后接动原，但否定和疑问句要借助do)：have to不得不，had better最好，used to过去常常 3.情态动词无三单(have to除外)；不能单独使用，后接动词原形共同构成谓语 4. need既可做实义动词又可做情态动词(作实义动词，后接to do/doing,否定don’t need to do do/doing;作情态动词，后接动词原形，否定needn’t do) 5.表推测：must be一定是（语气最肯定），can be可能是，may be也许是（语 气最不肯定）；can’t be一定不是（语气最肯定,must be的否定形式） 6.maybe也许(副词,常用在句首)；may be也许是(谓语动词，用在句中) 7.must与need开头的一般疑问句，肯定回答用must,否定回答用 needn’t/don’t have to(不必). 8.may开头的一般疑问句，肯定回答用may/can,否定回答用can’t/mustn’t. 二、系动词 1.系动词后可接形容词。 2.表示状态的系动词be(am, is, are, was, were,been),keep ,stay,表示感觉的 半系动词feel (摸起来，感觉), look (看起来), smell (闻起来), sound (听起来),taste(尝起来）; 三、助动词 1.助动词本身无词义或意义不完整，必须和实义动词共同构成谓语。 2.常用的助动词：be(am, is, are, was, were,been,being)用于进行时态或被动 语态；do(does,did)用于一般现在时或一般过去时的否定句和疑问句； have(has,had)用于完成时态；will,shall,would,should用于将来时态， shall/should只能用于第一人称。 情态动词与系动词练习题 一、基础题 1.-Where's Mr Lee I have something unusual to tell him. -You________ find him. He________ Japan. A. may not; has gone to B. may not; has been to C. can't; has gone to D. can't; has been to 2.-Finish drawing a horse in ten minutes. OK-Sorry. It________ in such a short time. A. may do B. can't be done C. must do D. needn't be done 3.I have my own room in my house, so I________do what I want in it. A. must B. have to C. need to D. can 4.________you mend my car I______not start it. A. Would; would B. Must; must C. Can; can D. May; may 5.________she ride when she was three years old A. Can B. Could C. Need D. May 6. The boy________answer this kind of hard questions one year ago. A. can B. may C. could 7.Who is the man over there Is it Mr Li-No, it________be him. Mr Li is much taller.
助动词和情态动词
第12章助动词和情态动词 1助动词和情态动词的定义 在英语中，助动词一般没有词义，主要帮助构成谓语，表示时态、语态或构成疑问及否定形式。对于助动词，同学们一般了解即可。 情态动词与助动词不同，它有词义，但它也和助动词一样，不能单独作谓语，它必须和其他动词一起构成谓语，另外重要的一点是情态动词没有人称和数的变化；情态动词后必须跟动词原形。 （×）She cans swim well. （×）She can swims well. （○）She can swim well. （○）She swims well. 即使主语是第三人称单数（例如she）can也不能加“s”。 句子中有情态动词can时，即使主语是第三人称单数，也不能在一般动词（例如swim）上加“s”。 1 助动词的种类 1.be（am，are，is，was，were，been，being）它与现在分词结合，可以构成进行时态（参见第九章），与过去分词结合可以构成被动语态（参见第十三章）。 I am reading the book.我正在读这本书。 The book was written by me.这本书是我写的。 2. have（has，had，having）它与过去分词结合，构成完成时态（参见第十一章）。 I have finished my homework.我已经写完作业了。
3.shall（should），will（would）它与动词结合构成将来时（参见第十章）。 I will visit Beijing tomorrow.我明天将到北京参观。 4. do（does，did）它与其他动词结合构成否定句和疑问句（参见第六、七、八、十九章）。 I don't like dog.我不喜欢狗。 Do you clean the room.你打扫房间吗？ 2情态动词的种类 对初学者而言，can，may，must是三个最重要的情态动词，其基本句型如下： 肯定句：主语+can，may，must +动词原形. 否定句：主语+can，may，must +not +动词原形～. 疑问句：Can，May，Must +主语+动词原形～？ I. can，may，must的肯定句 You may eat lunch，but you must wash your hands.你可以吃饭，但是你必须洗手。